Fusarium solani Upregulated Sesquiterpene Synthase Expression,Sesquiterpene Production and Allelopathic Activity in Piper betle L.

Activators of sesquiterpene synthase (STS) gene expression and sesquiterpene production in Piper betle L. were examined using quantitative real time PCR and gas chromatography mass spectrometry methods, and the allelopathic activity of untreated and Fusarium solani-treated betel extracts was tested on seed germination and on the shoot and root growth of Thai rice variety PSL2 (Oryza sativa cv. Phitsanulok 2) and three dominant paddy weeds (Eclipta prostrata, Echinochloa crus-galli and Chloris barbata). The results demonstrated that F. solani dramatically upregulated STS expression and productions of β-cubebene, β-caryophyllene and germacrene D sesquiterpene when compared with the untreated control, and that betel extracts had a greater inhibitory effect on weeds than on rice. The effects were more clearly detected on seed germination and root growth than on shoot growth, and they were found to be dose-dependent. It is also noted that F. solani-treated extract had stronger effects than the untreated extract. The species most sensitive to the allelopathic effects was C. barbata, germination of which was completely inhibited even at a dose of 0.1 mg/mL untreated extract. With regards to rice, although betel extract at 1.0 mg/mL showed no inhibition on germination, it affected the elongation of rice roots, in addition to those of the tested weeds. The obtained data suggested that F. solani has potential as an activator of sesquiterpene allelochemical production via STS expression, the latter leading to the treated betel extract having a stronger phytotoxic effect. These results were beneficial in the promotion of natural herbicide production using biotechnology.     

云南传统水稻品种W axy基因多样性形成和维持机制初探

本研究针对W axy基因第四外显子和第五外显子的3个功能位点开发了新的AS-PCR标记，完善了W axy基因的分子标记体系，为更精确的鉴定和筛选目标W axy等位基因提供了工具。直链淀粉含量测定和AS-PCR分析结果显示，云南传统水稻品种具有极为丰富的W axy基因多样性和直链淀粉含量变异，308个传统品种中共检测到65种不同的W axy单倍型，直链淀粉含量变幅为0~48%。In1、E6、E10和E4op/hp这4个位点的碱基频率在四大稻区间存在显著差异，E2位点和In1位点的碱基频率在不同民族间存在显著差异，表明不同稻作区、不同民族对水稻直链淀粉含量和W axy基因有着多样化的选择。同时民族混居地区E2和In1位点的碱基频率不同于其相应的民族独居地区，说明不同民族混居也会产生对W axy基因不同的选择并增加W axy基因的多样性。多样化的选择和民族混居是云南传统水稻品种W axy基因多样性形成和维持的重要机制。在云南四大稻作区中，南部边缘水陆稻区的W axy单倍型最为丰富，共检测到50种单倍型，占总数的77%，这一区域应被设为云南传统稻种资源的保护优先区和核心区。     

广西矿区大气沉降与稻米重金累积的关系分析(英文)

笔者就大气沉降的概念、来源及其危害作了简要的概述,并对广西矿区大气沉降与稻米重金属累积的关系作简要分析,以期对广西矿区重金属沉降污染实施有效的风险预警,确保稻米安全生产提供参考。     

Physicochemical characterization and in-vitro digestibility of extruded rice noodles with different amylose contents based on rheological approaches

The physicochemical properties and in-vitro digestibility of extruded rice noodles with different amylose contents were characterized from a rheological point of view. Thermo-mechanical measurements showed that the rice flour with higher amylose contents exhibited greater stability to dual-mixing and higher degrees of starch gelatinization and retrogradation. In addition, greater elastic properties were clearly observed in the high amylose rice samples. The use of high amylose rice flour produced noodles with a harder texture, consequently contributing to reduced cooking loss. Furthermore, the rheological changes of extruded rice noodles were monitored in real time during the in-vitro starch digestion. The rice noodle digesta with higher amylose contents exhibited greater viscosities throughout the simulated oral-gastric-intestinal digestion steps. The flow behaviors of the rice noodle digesta consisted of the Power-law region and infinite shear plateau that were satisfactorily characterized by the Sisko model (R² > 0.99).     

Screening of Drought Resistance Identification Indexes for Rice (Oryza sativa L.) Cultivars in Ningxia

The morphological characters, physiological characters, yield traits and yield per plant of total 49 rice cultivars from Ningxia were investigated under conditions of water stress and non-water stress so as to determine the relationship between each trait and yield per plant under water stress and the relationship between each relative character and drought resistance coefficient under water stress and non-water stress. The correlation, grey correlation, stepwise regression and path analyses showed that the til er number per plant, plant height, grain density, effective panicle number per plant and grain number per pan-icle, total 5 traits, were significantly correlated with the drought resistance of rice, and they could be used to identify the drought resistance of rice in Ningxia. In addition, the drought resistance of rice was graded qualitatively according to the subordinate function value of corresponding drought resistance coefficient. The results showed that among the 49 rice cultivars from Ningxia, 6 rice cultivars were highly drought resistant, and 9 rice cultivars were moderately drought resistant, suggesting that the evalua-tion method was feasible and effective.     

水稻高产、优质和氮高效协同的氮素调控研究

以超级粳稻‘新稻18号’为试验材料,大田条件下,研究不同施氮量(0、232.5、255.0、277.5、300.0、322.5和345.0kg/hm2纯氮水平)对水稻产量、品质及氮肥吸收利用效率的影响,以明确高产、优质和氮高效协同的适宜氮素水平。结果表明,随氮素水平提高,水稻产量、稻米品质和氮肥吸收利用效率均呈先增后降趋势。施氮量为255.0kg/hm2纯氮处理下,产量最高为9 878.11kg/hm2,稻米的糙米率、精米率和整精米率较高,分别为84.81%、72.85%和66.94%,垩白粒率和垩白度较低,分别10.00%和2.86%,氮肥吸收利用效率较高,为41.34%。低氮肥和高氮肥处理,产量、品质和氮肥利用效率相对较低。说明,在适宜的氮肥水平下,水稻高产、优质和氮高效可达到协同一致。     

Genotype-by-environment interaction analysis of rice (Oryza spp.) yield in a floodplain ecosystem in West Africa

West Africa has large areas of river floodplains, most of which are not currently used for farmland. Rice (Oryza spp.) is a promising crop for farming in floodplains because of its high adaptability to a wide range of water environments. On the other hand, there is great variation in soil fertility and water availability even in a small area within a floodplain. Hence, we evaluated 27 rice genotypes in four fields in three years in a floodplain of the Northern Region of Ghana to investigate genotype × environment (G × E) interactions for rice yield and to identify stable, high-yielding genotypes. The genotypes consisted of O. sativa, O. glaberrima and New Rice for Africa (NERICA), and many were selected for their reported submergence resistance because of the anticipated submergence damage in the floodplain. There were large variations in yield, which ranged from 0.14 to 5.35 t ha⁻¹ depending on the location within a floodplain, genotype and year, and there were significant genotype, environment and G × E interaction effects on yield, accounting for 24.8%, 20.2%, and 28.2%, respectively, of the total variation. The results suggested that selection of suitable location with high soil fertility and low risk of submergence is necessary to achieve high yield in a floodplain. In addition, early sowing would be effective high-yielding crop management, which reduced the risk of submergence-induced damage just after sowing and secured sufficient growth duration to achieve high yield. Genotype IR42 showed the highest average yield among environments, but its yield stability was low. On the other hand, several genotypes including Amankwatia, a local aromatic cultivar adapted to irrigated and lowland environments, and IRBL9-W[RL], a blast-tolerant variety containing the Sub1 gene for submergence tolerance, showed high, stable yield. To put these results to practical use in other floodplain areas in West Africa, physiological mechanisms causing G × E interaction for rice yield should be further studied.     

施钾量对超高产早稻品种产量和稻米品质的影响

以超高产水稻品种陆两优996和淦鑫203为材料,在大田条件下研究了不同施钾量对其产量和稻米品质的影响。结果表明,施钾显著提高双季早稻有效穗数、每穗粒数和产量,增加生物产量、促进茎鞘物质运转,提高抽穗期剑叶的气-叶温差和颖花伤流量,降低抽穗后的根系活力衰退值。施钾量与倒1节间大维管束数、茎秆抗折力和稻米蛋白质含量显著正相关。施钾提高了陆两优996的垩白粒率和垩白度,但降低了淦鑫203的垩白粒率和垩白度。在本试验条件下,最适施钾量为180 kg/hm2。     

一个水稻三倍体×二倍体杂交F2群体的微卫星杂合性丧失

DB102为一田间发现的三倍体水稻,利用它做母本与二倍体水稻中作59杂交,得到一个早世代(F2)稳定群体,通过微卫星分析发现,该群体中有一些微卫星位点发生了杂合性丧失,且至少6条染色体上发生微卫星位点杂合性丧失(loss of heterzygoisity LOH)可能有DNA序列变化。而微卫星位点的杂合性丧失又可能与该杂交组合早世代稳定有关。     

提高水稻愈伤组织再生频率的研究

以长时间继代的水稻成熟胚愈伤组织为试验材料,研究激素配比、继代方式、干燥处理和添加物对分化的影响。结果表明,分化培养基中加3 mg/L BA对分化有利;继代培养基中加入3 mg/L ABA,以麦芽糖代替蔗糖,或以甘露醇代替部分蔗糖在一定程度上可以改善愈伤组织状态,提高分化率;干燥处理能明显提高愈伤组织分化率;分化培养中添加一定浓度的AgNO3和CuSO4有利于愈伤组织分化。